Post navigation

2015年2月、オープンキャンパスで「アリのふしぎ」の展示をしました

Submitted by Yoshimura-san

The Economo Unit once again setup the booth, “Wonders of Ants,” at OIST’s Open Campus, which took place on February 1st, 2015. We displayed 2D and 3D ant images, research posters, ant trivia, ant specimens and live colonies to show our ant research. Many visitors enjoyed the displays, and learned about the diversity of ants and their important role in the ecosystem. Some people were surprised to see the stout head of the Okinawan trap-jaw ant, Odontomachus kuroiwae. Some were amazed by the high diversity of ants found on Okinawa Island. Many kids were glued to the live colony displays, and to the 3D image. We also asked visitors to draw ants. By the end of the day, we had three large posters filled with colorful drawings of ants!

Very happy to report the new paper on Pheidole from the lab, in collaboration with Lacey Knowles’ lab at U. Mich. We update the global phylogeny to around 300 species, and find some interesting relationships between the phylogenetic and macroecological structure of the genus. Also check out the story on the OIST website. This one has been a long time coming and a lot of work. Look for more work and bigger trees on Pheidole coming soon.

We are pleased to welcome Georg Fischer to the lab, our new Postdoctoral Scholar. Georg originally hails from Germany, but more recently was a postdoc at the California Academy of Sciences for several years. He is going to be taking a leading role in our projects on the biogeography, ecology, phylogeny, and systematics of the hyperdiverse ant genus Pheidole. Georg has worked particularly on the Afrotropical and Malagasy Pheidole, and will continue that work but also put it in context of the major Old World Pheidole radiations.

Onna-son and OIST organized a summer science school for children from the 18th to the 22nd of August, 2014. Members of Economo Unit participated and held a class for 1st to 3rd grade students from local schools.

The theme of the class was of course “The Ants!” Students enjoyed a science quiz about morphology and ecology of ants, and learned about this wonderful insect, which, although quite common and familiar, is actually very mysterious.

We started by demonstrating an experiment for the students where we fed colored honey to the Yellow Crazy ants. Soon after, the colors could been seen in the gasters of the ants. Then the students collected ants by themselves and observed them under the microscopes in search for answers to the quiz questions. By the end of the quiz, they were full of many new questions! They were amazed to find out that many different species, each with varying appearances and morphology, live under their feet.

Recently, Arilab post-doc Beatrice Lecroq participated in a research expedition to Kermadec Trench. Here is her account:

Research Vessel Thomas G. Thompson docked in Auckland

“From April 10 through May 20, I took part in the HADES cruise on-board research vessel Thomas G. Thompson to the Kermadec Trench. The trench runs from New Zealand to Louisville Seamount chain (south of Samoa) and reaches 10,047 m depth. HADES (HADal Ecosystems Studies) is a collaborative project founded by the National Science Foundation and aims to investigate the major environmental drivers of trench ecology. I joined this expedition together with 32 other scientists from 11 different institutions having the common motivation of tackling some mysteries about the evolution of life in trenches.

My specific interest was focusing on the diversity of benthic foraminifera (unicellular eukaryotes belonging to Rhizaria supergroup). Following the resource availabilities, deep-sea ecosystems are either patchy and transient or stable and oligotrophic. I think that benthic foraminifera have progressively coped with both situations by evolving into either opportunistic and generalist species or highly specialized taxa, which greatly contribute to their high richness (around 4000 species described and more than 10,000 estimated) and spectacular morphological diversity. In the sediment along the trench axe and up its flank onto the adjacent abyssal plain, foraminifera dominate the meiofauna, which conventionally ranges from 45 µm to 1 mm. However, evolutionary specialization led some taxa – the xenophyophores – to drastically increase their size (up to 20 cm in diameter) and to display some genuine properties such as accumulation of heavy metals from the water column into their shells. Although they are some of the largest single-celled organisms and can occur in extremely high densities (up to 20 specimens per square meter), information about this group, its diversity, biology, and ecology, remains scarce. Their large shells also attract a wide variety of life, including isopods, polychaetes, mollusks, and echinoderms, which indicates that they could be used as bioindicators for environmental pollutant concentrations and local/regional species diversity.

Nereus Hybrid Remote Vehicle

Using the remotely operated vehicle Nereus, coupled with push cores and a 4K resolution camera, we explored 5 sites ranging from 6,000 to almost 10,000 meters in depth and sampled undisturbed sediment and isolated specimens including xenophyophores. After recovering on deck, raw sediment from different layers (from the surface of the sediment to the core bottom) was flash frozen for later extraction of environmental DNA/RNA. In the future, foraminifera genomic DNA molecules will be amplified via PCR using specific primers and then massively sequenced. Fresh xenophyophore specimens were incubated in a buffer, fluorescently labelling any protein activity, to illuminate living organisms associated with their shells. The material we collected during this cruise will help in answering the following questions:

What is the foraminiferal/xenophyophores richness of the Kermadec Trench? What organisms are associated with xenophyophores shells?

What is the spatial variation of foraminiferal richness at a regional scale along the trench axis and how is this richness related to those found in other trenches?

What is the metabolic activity of the communities (reflected by environmental RNA)? Is the trench environment a general trap/depository for extracellular DNA from the surrounding slopes and abyssal plains?

Xenophyophore specimen recovered from a push core

Retrieving push core from 7000m

This cruise was ambitious and certainly not devoid of technical hurdles. After many hours of observation and sampling at the bottom of the trench, the Nereus submersible imploded at the end of the deepest dive, close to 10,000 m. The deepest cores and their sediments were lost, but images, video transects, as well as the material of the 5 previous dives, was recovered successfully. Despite the accident, the effort might be one of the most informative pieces of sampling from this mysterious region.”